A pattern of symbols is generated and sent to a projector, wherein the pattern includes an array of symbols having a given number of symbol columns and symbol rows, and an image is obtained from a camera. Next the image is decoded in order to generate a decoded pattern of symbols and the depth map is generated as a function of the pattern and the decoded pattern. The image is decoded by placing an array of classification windows on the image and determining the displacement of each classification window in order to optimize a given cost function. Finally, the decoded pattern is generated by determining a respective symbol for each classification window.